Data centers may include host server devices and network virtualization edge (NVE) devices. A NVE may include a network device that sits at the edge of an underlay network (e.g., a data center network) and implements layer 2 (L2) and/or layer 3 (L3) network virtualization functions. In one example, assume that NVEs in different data centers need to be interconnected, and that the NVEs use virtual network identifiers (VNIs) as unique identifiers within each data center. The VNIs may be unique within each data center but not across the data centers due to separate data center network management or a controller not spanning the data centers.